The day before place the pork, rind-side down on a chopping board. Cut into the thickest part of the pork along the long side, three-quarters of the way through to form a flap. Evenly sprinkle over the fennel seeds, black pepper, chilli flakes, cloves, and sage leaves.
Roll pork up firmly from the long side and tie with kitchen string at 5cm intervals. Place on a small wire rack and leave uncovered in the fridge overnight.
Allow the pork to come up to room temperature. Rub pork skin with olive oil and salt flakes, massaging well into skin.
Preheat microwave to convection 220°C.
Roast pork for 60 minutes, until the crackling has formed. When the microwave beeps, Place the oven on 150°C and cook for a further 20 minutes.
When cooking is complete, remove from the microwave and allow to rest for 15 minutes before slicing.